Social norms intervention strategies are widely used on college campuses to reduce heavy drinking and alcohol-related harm. There is strong evidence that students misperceive (overestimate) the level of drinking that is normative among their peers, and it is argued that normative pressure contributes to heavy drinking. By providing drinkers with accurate normative information, social norms approaches attempt to change peoples'erroneous normative beliefs and, consequently, reduce their drinking. However, evaluations of social norms marketing strategies as implemented on college campuses are poor tests of the general applicability of social norms theory to reducing drinking. The research proposes to examine experimentally the impact of providing drinkers with normative drinking information in a controlled, real-world drinking environment. Young U.S. residents will be sampled at the Mexican border at San Diego before they cross into Tijuana. Participants'drinking plans and normative beliefs will be measured, and then participants will be randomly assigned to experimental conditions where they will receive different types of accurate normative drinking information. These same participants will be resampled as they return from Tijuana and their drinking levels will be measured objectively through a BAG breath test. The research will examine whether participants'drinking while in Tijuana was impacted by the normative information. Although social norms research typically has been conducted on college students, this research will be novel in that it will test a social norms intervention on a diverse drinking population. In addition to testing whether a brief, face-to-face normative drinking intervention affects short-term alcohol consumption, we will manipulate several variables hypothesized to moderate the impact of that intervention. Communication persuasion theory suggests that normative information should be more persuasive to the extent that recipients attend to it, believe the information, and believe that it is personally relevant. We will examine whether varying the persuasive properties of the normative information effects in the impact of participants'alcohol consumption. This research will contribute both to the theoretical understanding of social norms mechanisms, as well as address ways to increase its applicability to real-life interventions. Public Health Relevance: Student drinking poses a serious threat on college campuses. Social norms marketing strategies are widely used to reduce alcohol consumption on campus;however, the effectiveness of these strategies has been mixed. This research will help identify factors that might improve the efficacy of social norms interventions.